diff --git a/mm/bootmem_info.c b/mm/bootmem_info.c
index e61e08e24924..3d7675a3ae04 100644
--- a/mm/bootmem_info.c
+++ b/mm/bootmem_info.c
@@ -44,17 +44,16 @@ static void __init register_page_bootmem_info_section(unsigned long start_pfn)
 {
 	unsigned long mapsize, section_nr, i;
 	struct mem_section *ms;
-	struct page *page, *memmap;
 	struct mem_section_usage *usage;
+	struct page *page;
 
+	start_pfn = SECTION_ALIGN_DOWN(start_pfn);
 	section_nr = pfn_to_section_nr(start_pfn);
 	ms = __nr_to_section(section_nr);
 
-	memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
-
 	if (!preinited_vmemmap_section(ms))
-		register_page_bootmem_memmap(section_nr, memmap,
-				PAGES_PER_SECTION);
+		register_page_bootmem_memmap(section_nr, pfn_to_page(start_pfn),
+					     PAGES_PER_SECTION);
 
 	usage = ms->usage;
 	page = virt_to_page(usage);